[ Summary of the invention ]
The invention relates to a method for enabling vehicle functions based on visual recognition of a user by means of an enabling device comprising at least one camera oriented towards the outside of the vehicle and equipped with visual recognition means, and at least one ultra-wideband transceiver capable of detecting the presence of a body inside the vehicle, the method being notable in that firstly the transceiver is modified to allow the transceiver to transmit to the outside of the vehicle at different refresh rates, and in that the method comprises the following steps:
a) An ultra-wideband wave is transmitted to the exterior of the vehicle at a first refresh rate,
B) The reflected wave is received and the reflected wave is received,
C) Detecting the presence of a body in a predetermined area around the vehicle,
D) The refresh rate is adjusted according to the distance (d) between the presentity and the vehicle, with a higher frequency when the presentity is close to the vehicle,
E) The camera is only enabled when the presence of a body has been detected at a distance below the threshold,
F) The presence body is identified by visual recognition,
G) If the presentity is identified as the user, the vehicle function is enabled.
Preferably, the value of the refresh rate varies from 1Hz to over 100Hz.
Advantageously, the distance is determined by calculating the time of flight of the wave and/or by calculating the offset between the frequency of the transmitted wave and the frequency of the received reflected wave.
The invention also relates to a device for enabling vehicle functions, the enabling being triggered by visual recognition of a user, the enabling device comprising at least one camera oriented towards the outside of the vehicle and equipped with visual recognition means, and at least one ultra-wideband transceiver capable of detecting the presence of a body inside the vehicle, the device being notable in that said transceiver is modified so as to transmit towards the outside of the vehicle, and in that the device further comprises:
a) Changing means for changing a refresh rate of the emitted wave,
B) A detecting device for detecting an existing body in a predetermined area around the vehicle and for adjusting the detecting device according to a position of the existing body,
C) Frequency adjustment means for adjusting the refresh rate in accordance with the distance between the existing body and the vehicle, the frequency being higher when the existing body approaches the vehicle,
D) Camera enabling means for enabling the camera only when the presence of the body has been detected at a distance below a threshold value,
E) A vehicle function enabling means for enabling a vehicle function according to a result of identifying the presentity by visual recognition.
Advantageously, the value of the refresh rate varies between 1Hz and more than 100 Hz.
The detection means for detecting and for adjusting the device comprise, judiciously, means for calculating the time of flight of the wave and/or for calculating the offset between the frequency of the transmitted wave and the frequency of the received wave.
The invention also relates to any computer program product comprising program code instructions for performing the steps of a method according to any of the features listed above, when said program is executed on a computer.
Finally, the invention is applicable to any motor vehicle comprising an enabling device according to any of the features listed above.
Detailed description of the preferred embodiments
Fig. 1 shows a motor vehicle V equipped with a device D for enabling vehicle functions according to the invention.
The vehicle function may be to lock or unlock an opening of the vehicle V, such as unlocking the driver door P, i.e. taking the vehicle V.
The activation of the function is triggered by visual recognition of the user authorized to use the vehicle V. The vehicle V has performed pre-authentication of the user's face in order to record and store data relating to the user's face in order to authorize subsequent retrieval requests.
Visual identification for access equipment is known to those skilled in the art and will not be described in further detail herein.
According to the invention, the enabling device D comprises at least one camera C1, C2 oriented towards the outside of the vehicle and equipped with visual recognition means, and an Ultra Wideband (UWB) transceiver EM1 able to detect the presence of the vehicle interior. In the example illustrated in fig. 1, two cameras C1, C2 are located on both sides of the driver door P.
Thus, the camera C1 is able to visually display any object close to the vehicle, preferably close to the opening (here the door intended to be locked or unlocked), on the side where the camera is fixed.
The Ultra Wideband (UWB) transceiver EM1 itself is preferably located inside the vehicle V and is used to detect the presence of any presence in the passenger compartment, for example of children.
In the example illustrated in fig. 1, two transceivers EM1, EM2 are located in the passenger compartment of the vehicle V. Two transmitters instead of only one enables a more accurate localization of the presence in the passenger compartment.
According to the invention and contrary to the prior art, the transceivers EM1, EM2 have been modified so as to emit UWB waves extending outside the passenger compartment in a predetermined zone Z3, Z11, Z21 around the vehicle V (for example within a radius of 5 meters around the vehicle V).
For this purpose the transceivers EM1, EM2 have been modified in that each transmitter comprises two antennas, one oriented towards the interior of the vehicle V and one oriented towards the exterior of the vehicle V, whereby these antennas have different radiation due to their orientation.
A switch is connected to the two antennas and allows selection of one or the other of the two antennas. Such devices are known from the prior art.
Alternatively, each transceiver comprises two antennas oriented in the same way but out of phase, and in the case of opposite phases, the radiation pattern so produced is oriented both towards the inside of the vehicle V and towards the outside of the vehicle. Such devices are also known from the prior art and will not be further developed here.
The enabling device D further comprises a central control unit 10 electrically connected to the transceivers EM1, EM2 and the cameras C1, C2.
The central control unit 10 is used for managing the transmission and reception of UWB waves by means of the transceivers EM1, EM2, but also for triggering the activation or the deactivation of the cameras C1, C2 and for processing information from said cameras. Thus, the central control unit 10 also comprises image processing and visual recognition means. This is known in the art and will not be described in more detail here.
Ultra Wideband (UWB) communication refers to radio frequency communication based on pulse transmissions of very short duration (typically less than one nanosecond). Thus, the bandwidth may reach values between 250MHz and 500MHz and even higher.
According to the invention, the enabling device D further comprises:
a. changing means M1 for changing the refresh rate F of the emitted wave,
B. A detecting means M2 for detecting a present body in a predetermined area around the vehicle and for adjusting the device according to the position of the present body,
C. frequency adjustment means M3 for adjusting the refresh rate F in accordance with the distance d between the presentity and the vehicle, the frequency being higher when the presentity approaches the vehicle,
D. Camera enabling means M4 for enabling the camera only if an presentity has been detected at a distance d below a threshold value,
E. And vehicle function enabling means M5 for enabling a vehicle function according to the identification result of the presentity by visual recognition.
The changing means M1, the detecting means M2, the frequency adjusting means M3, the camera enabling means M4, and the vehicle function enabling means M5 are preferably in the form of software included in an integrated circuit of the central control unit 10 (see fig. 4).
The refresh rate F is understood to mean the number of frames transmitted per second. Each frame contains waves of a plurality of predefined durations (e.g., 5 ms). The refresh rate is thus used to adjust the speed at which the UWB transceivers EM1, EM2 receive data in their coverage areas.
Thus, according to the present invention, the changing means M1 is able to change the refresh rate F of the UWB transmission wave from f0=1 Hz to more than f2=100 Hz. The higher the refresh rate F, the more energy the transceiver consumes (here, power from the battery of the vehicle V) and the more accurate the positioning of the presentity. Conversely, the lower the refresh rate F, the less energy is consumed by the transceivers EM1, EM2, but the more inaccurate the positioning of the presentity.
The present invention proposes to use the variation of the refresh rate F to accurately detect the presence of a body in the zone Z11, Z21 close to the vehicle V and therefore to activate the cameras C1, C2 to trigger visual recognition only when the presence is in the zone close to the vehicle V, while saving energy in the battery.
The detection means M2 for detecting the presence of a body in a predetermined area and for adjusting the device according to the position of the presence relative to the vehicle or relative to the predetermined area comprises:
a. Device for calculating a frequency offset between the frequency of a transmitted wave and the frequency of a received reflected wave, and
B. device for calculating the time of flight of waves in a round trip between a transceiver EM1, EM2 and a living being, and
C. means for determining the angle of arrival of the reflected waves received by the transceivers EM1, EM 2.
These different means are known to the person skilled in the art.
In order to reduce the power consumption, the detection means M2 consist only of means for calculating the frequency offset when the refresh rate is slow (for example f0=1 Hz) but sufficient to detect the presence of a body in the predetermined zone Z3 furthest from the vehicle V. These devices are of the doppler radar type. In order to detect the presence in the predetermined zones Z11, Z21 close to the vehicle, the time of flight of the wave and the angle of arrival of the reflected wave are determined in order to obtain a more accurate position of the presence around the vehicle V and thus calculate the distance d of the presence from the vehicle V.
Alternatively, in the case of two transceivers EM1, EM2, triangulation or cross-referencing between the data of the two transmitters still allows accurate positioning.
If the transceiver EM1, EM2 has detected a presence in the zone Z11, Z21 (see fig. 2) close to the surroundings of the vehicle, i.e. only if said presence is located at a distance d from the vehicle below a predefined threshold, the camera enabling means M4 are used to activate one or more cameras C1, C2.
Finally, the vehicle function enabling device M5 locks or unlocks the opening of the vehicle V according to the result of visual recognition of the user U in the images captured by the cameras C1, C2.
According to the embodiments described below, the central control unit 10 further comprises a processor 100 and a memory 101 (see fig. 4), in which instructions are stored, which allow the processor to be configured to perform certain specific processing operations, in particular to implement the steps of the enabling method.
The enabling method shown in fig. 5 will now be described. The method demonstrates that the enabling function is to unlock the opening of the vehicle V.
In a first step E1, the transmission of ultra-wideband waves in a predetermined zone Z3 (i.e. within a radius of about 5 meters around the vehicle V) using a first low refresh rate F0 of about 1Hz is triggered by the transceivers EM1, EM 2. The advantage of this emission mode of emission at a very low refresh rate F0 is that the power consumption is very small (about 10 mW).
If a human presentity or object is located in the predetermined zone Z3 (i.e., the zone furthest from the vehicle V) (step E1), the transmitted wave will be reflected by the presentity and then received back by the vehicle V. This is shown on the left side of fig. 3.
The reflected wave is processed and analyzed, for example, a frequency offset is calculated, which is used to detect the presence of a body in a predetermined area Z3 (for example, 5 meters around the vehicle V) as in the case of a doppler radar.
If there is a bank in the predetermined area (step E1), the refresh rate is increased to a second value F1, which is greater than the first value, for example about 10Hz. Emitting waves at this refresh rate F1 (step E2) will of course consume more energy, about 150mW, but allow to more accurately determine the position of the presentity and confirm its association with the predetermined zone Z3.
This is illustrated by the middle diagram in fig. 3.
If it is confirmed that the presentity is located in the predetermined zone Z3 away from the vehicle (step E3), the refresh rate is increased to a third value F2 of approximately 100 Hz. At this speed, the power consumption is still higher, about 300mW, but the emission of waves at this frequency (step E4) makes it possible to determine whether the presentity has moved closer to the vehicle and is now located in the zone Z11, Z21 close to the vehicle V, for example within a radius of 2 meters around the vehicle V, and makes it possible to accurately locate the presentity. This is shown on the left side of fig. 3.
In this case, the invention proposes to use the calculation of the time of flight in combination with the calculation of the frequency offset between the transmitted wave and the received wave and optionally the determination of the angle of arrival of the reflected wave in order to more accurately estimate the distance d between the presentity and the vehicle V.
If a presence body is located in the proximity zone Z11, Z21 (step E5), the use of the transceivers EM1, EM2 as doppler radars makes it possible to detect the presence body in the coverage area of the transmitter (i.e. 5 meters around the vehicle) and thus the intrusion of the presence body in this zone Z3.
The use of the time of flight and the angle of arrival itself makes it possible to locate the presentity more accurately and to find out whether the presentity is located in the zone Z11, Z21 close to the vehicle in order to enable the cameras C1, C2. Thus, not only the refresh rate is to be adjusted according to the position of the presentity, but also the detection means for detecting the presentity.
If the presentity is located at a distance d below a predefined threshold, e.g., less than 2 meters from the vehicle, cameras C1, C2 are enabled (step E6) to capture an image of the presentity.
Then, the face of the user U authorized to enter the vehicle V is identified or not identified (step E7) using image processing software. If the user U is authenticated (step E7), the function is enabled (here, unlocking the opening) (step E8 a), whereas if the result of the visual recognition is that no authorized user is recognized, the function is not enabled (step E8 b).
In the case of locking, the steps (not shown) are as follows. In a first step, UWB waves are transmitted to the outside of the vehicle at a first frequency f0=100 Hz, and then reflected waves are received by the enabling device D. The first refresh rate F0 used is highest when the enabling device D that the user was previously used to detect the presence of a body in the passenger compartment is detected as being inside the vehicle. Analyzing and processing the frequency of the received wave and/or the round trip time of flight of the wave makes it possible to determine the distance d the user U is spaced from the vehicle V.
When the user leaves his vehicle, the distance will be below the threshold value, because the user U is located in the zone Z11, Z21 close to the vehicle V.
In this case, one or more cameras C1, C2 are enabled to capture an image of the presentity, and then to implement visual recognition of the presentity.
If the user is identified as authorized to access his vehicle V, a lock on the opening is triggered.
The invention is particularly inventive in that it saves energy and requires little modification and is therefore inexpensive.